Jeep’s flagship Grand Cherokee sport utility vehicle is so improved for 2011, passengers might think they’re riding in a luxury vehicle.The interior of the new Grand Cherokee is impressively quiet, with supportive seats and well-arranged controls. Exterior styling is more rounded and modern than before, and the new V-6 engine is more robust than its predecessor. Best of all, the vehicle rides in a nearly refined manner on pavement, while still capably handling rugged off-road duty when needed.But don’t look for a bargain price. With seats for five, Grand Cherokees remain in the $30,000-and-above category, though starting retail price has declined by $499.Specifically, starting manufacturer’s suggested retail price, including destination charge, is $30,995 for a 2011 Grand Cherokee with rear-wheel drive, automatic transmission and new, 290-horsepower V-6. This contrasts with the $31,490 price for a base, 2010 Grand Cherokee with 210-horsepower V-6. With four-wheel drive, the 2011 Grand Cherokee starts at $32,995, and the top-level Overland model starts at $42,690. Substituting a 360-horsepower, 5.7-liter, Hemi V-8 under the hood adds $1,495 to the price, no matter the model of Grand Cherokee.Competitors in the traditional SUV segment have been dwindling as Americans turn to lighter-weight, less brawny and more fuel-efficient crossover SUVs with car-like ride.But Nissan’s 2011 Pathfinder, which has a starting retail price of $28,640 with 266-horsepower V-6, and Toyota’s 2011 4Runner with 270-horsepower and starting retail price of $30,335, are among those remaining. The Pathfinder and 4Runner each offer a third row of seats, but the Grand Cherokee does not.The Jeep brand — which dates to tough, nimble, off-road vehicles used in World War II — is well known for its rugged image. So it’s the smooth, easy-travel ride of the new Grand Cherokee that was most striking and memorable.In contrast with earlier Grand Cherokees, I didn’t feel a lot of road bumps underneath me. Most were stifled and managed adeptly by the new, independent front and rear suspensions with isolated suspension cradles. The previous Grand Cherokee had a live rear axle, instead.Also note that the platform under the new Grand Cherokee is used by the pricier and tonier Mercedes-Benz ML-Class SUV. This is because the development of the 2011 Grand Cherokee began years ago, when Mercedes’ parent company owned Chrysler, which is the parent company of Jeep.All this, plus a much more rigid body and newly tuned rack-and-pinion steering, allowed Jeep engineers to improve the ride and handling of the Grand Cherokee markedly.The base, 3.6-liter, double overhead cam, Pentastar V-6 is new, too. Jeep boasts the powerplant is more fuel efficient than the lower-powered, base, 3.7-liter V-6 from last year. But the federal fuel economy rating of 16 miles per gallon in city driving and 22 mpg on the highway for a four-wheel drive, 2011 Grand Cherokee like the one I tested ranks in the lower half of SUVs on the market. I averaged 18.9 mpg over city and highway miles, without really trying to wring everything I could from the regular gasoline.But I was extremely satisfied with the engine’s performance — no stressing for get-up-and-go, easy cruising and inspired, but not thundering, response in city driving. Torque peaks at 260 foot-pounds at 4,800 rpm and seemed well matched for the 4,470-pound model with four-wheel drive that was the test vehicle.In fact, I wondered if I were to buy a Grand Cherokee whether I would be interested in upgrading to the top engine — a 360-horsepower, 5.7-liter, Hemi V-8 with 390 foot-pounds at 4,250 rpm. The fuel mileage rating drops to 13/19 mpg for a four-wheel drive Grand Cherokee with the Hemi.Still, it’s worth noting how large the Grand Cherokee fuel tank is. It holds 24.6 gallons, so the test vehicle could go well over 450 miles without a fillup, even with the kind of mileage I got.Everyone in the Jeep appreciated the good views out as we rode high above the pavement. But the seat cushion height wasn’t so high that I had to struggle to climb aboard.Ground clearance under the Grand Cherokee is a healthy 8.6 inches, and the front and rear body styling maximizes approach and departure angles for off-road situations.There are many features that Jeep continues to provide for committed off-roaders. These include a traction control system where a driver can select the type of terrain to maximize control and grip. Also, a Quadra-Lift air suspension system can raise the vehicle body by up to 4.1 inches above obstacles. But fewer than 8 percent of Grand Cherokee buyers go off-road.I appreciated the excellent fit and finish on the tester, and the cargo area behind the rear seats is bigger now — 35.1 cubic feet vs. less than 30 cubic feet last year.Rear seats have more legroom — now 38.6 inches. This is a bit more than the 38.3 inches reported in the second row of the Toyota 4Runner and the 34.2 inches in the second row of the Nissan Pathfinder. It’s comfortable riding back there, too, because 39.2 inches of headroom is nearly as much as the people in the front seat get. Front and rear door openings are larger this year, making it easier to get in and out of the Grand Cherokee.Many safety features are standard, including antilock brakes, electronic stability control, curtain air bags and even hill descent control.Government crash tests gave four out of five stars for Grand Cherokee passenger protection in a frontal crash and five out of five stars in a side crash.